Commit ba026334 authored by Noralf Trønnes's avatar Noralf Trønnes Committed by Daniel Vetter

fbdev: fb_defio: Export fb_deferred_io_mmap

Export fb_deferred_io_mmap so drivers can change vma->vm_page_prot.
When the framebuffer memory is allocated using dma_alloc_writecombine()
instead of vmalloc(), I get cache syncing problems on ARM.
This solves it:

static int drm_fbdev_cma_deferred_io_mmap(struct fb_info *info,
					  struct vm_area_struct *vma)
{
	fb_deferred_io_mmap(info, vma);
	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

	return 0;
}

Could this have been done in the core?
Drivers that don't set (struct fb_ops *)->fb_mmap, gets a call to
fb_pgprotect() at the end of the default fb_mmap implementation
(drivers/video/fbdev/core/fbmem.c). This is an architecture specific
function that on many platforms uses pgprot_writecombine(), but not on
all. And looking at some of the fb_mmap implementations, some of them
sets vm_page_prot to nocache for instance, so I think the safest bet is
to do this in the driver and not in the fbdev core. And we can't call
fb_pgprotect() from fb_deferred_io_mmap() either because we don't have
access to the file pointer that powerpc needs.
Signed-off-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Acked-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1461856717-6476-5-git-send-email-noralf@tronnes.org
parent eaa434de
...@@ -164,7 +164,7 @@ static const struct address_space_operations fb_deferred_io_aops = { ...@@ -164,7 +164,7 @@ static const struct address_space_operations fb_deferred_io_aops = {
.set_page_dirty = fb_deferred_io_set_page_dirty, .set_page_dirty = fb_deferred_io_set_page_dirty,
}; };
static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma) int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
{ {
vma->vm_ops = &fb_deferred_io_vm_ops; vma->vm_ops = &fb_deferred_io_vm_ops;
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
...@@ -173,6 +173,7 @@ static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma) ...@@ -173,6 +173,7 @@ static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
vma->vm_private_data = info; vma->vm_private_data = info;
return 0; return 0;
} }
EXPORT_SYMBOL(fb_deferred_io_mmap);
/* workqueue callback */ /* workqueue callback */
static void fb_deferred_io_work(struct work_struct *work) static void fb_deferred_io_work(struct work_struct *work)
......
...@@ -673,6 +673,7 @@ static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, ...@@ -673,6 +673,7 @@ static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch,
} }
/* drivers/video/fb_defio.c */ /* drivers/video/fb_defio.c */
int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma);
extern void fb_deferred_io_init(struct fb_info *info); extern void fb_deferred_io_init(struct fb_info *info);
extern void fb_deferred_io_open(struct fb_info *info, extern void fb_deferred_io_open(struct fb_info *info,
struct inode *inode, struct inode *inode,
......
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